Associations between ultrasound-detected osteophytes at baseline (independent variables) and incident radiographic or clinical OA at follow-up (dependent variables in separate models)
| Dependent variables | Incidence (percentage) | OR (95% CI) | ||
| Joints with ultrasound-detected OP at BL | Joints with no ultrasound-detected OP at BL (ref.) | Crude | Adjusted* | |
| a) Joints without radiographic OA (KLG=0) at BL (n=301) | ||||
| Incident radiographic OA (KLG ≥1) at FU | 40/86 (46.5) | 37/215 (17.2) | 2.9 (1.6 to 5.4) | 4.1 (2.0 to 8.1) |
| Incident radiographic JSN ≥1 at FU | 15/86 (17.4) | 9/215 (4.2) | 4.2 (1.8 to 10.2) | 5.3 (2.1 to 13.4) |
| Incident radiographic OP ≥1 at FU | 31/86 (36.0) | 28/215 (13.0) | 2.9 (1.6 to 5.4) | 4.2 (2.1 to 8.5) |
| b) Joints without or doubtful radiographic OA (KLG=0–1) at BL (n=487) | ||||
| Incident radiographic OA (KLG ≥2) at FU | 67/203 (33.0) | 25/284 (8.8) | 4.0 (2.3 to 7.1) | 5.5 (2.9 to 10.4) |
| c) Joints without clinical OA (no bony enlargement) at BL (n=718) | ||||
| Incident bony enlargement at FU | 237/392 (60.5) | 86/325 (26.5) | 3.4 (2.4 to 4.8) | 3.5 (2.4 to 5.1) |
Generalised estimating equations presented as ORs for development of OA features at follow-up with separate models for each feature.
*Adjusted for age, sex, body mass index and FU time.
BL, baseline; FU, follow-up; JSN, joint space narrowing; KLG, Kellgren-Lawrence grade; OA, osteoarthritis; OP, osteophytes; ref, reference in regression analyses.